Avalanche Forecast

Issued: Jan 22nd, 2016 4:13PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs and Loose Dry.

Lisa Paulson, Parks Canada

Banff Yoho Kootenay.

Rein it in this weekend...Thurs-Fri storm left touchy wind slabs on lee features.AVALANCHE CONTROL planned for Mt. Bosworth, Stephen and Dennis on Saturday. Please no recreational activities

Summary

Weather Forecast

Over Friday night temperatures and winds will drop and snow/rain will taper off. Over the weekend, expect cloudy skies, light to moderate ridge wind, and alpine highs in the single digits. No significant flurries for the next several days.

Snowpack Summary

Ongoing storm Friday night is continuing to move the 20-30cm recent snow, forming wind slabs at treeline and above. The moist storm snow and wind slabs overlie weak facets. Below treeline snow was still unaffected by wind on Thursday-Friday, but this could change quickly with Friday nights weather. On Friday there was light rain to 1800 m.

Avalanche Summary

One size 2 observed near Sunshine, N aspect where a thin windslab stepped down to 60-80 cm, propagated 80 m, & ran full path (200 m). Control work on Mt. Bourgeau produced numerous avalanches size 1- 2. One started as a wind slab & entrained all of the facets in the track, hitting the road. This is consistent with other observations this week.

Confidence

Problems

Wind Slabs

Forecasted strong Westerly winds and new snow will continue to form touchy wind slabs over the previous facetted surfaces. Once initiated, these can gouge down to the facets and run further than expected, especially in thin snowpack areas.

Avoid lee and cross-loaded terrain near ridge crests.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Loose Dry

With forecasted weather, natural loose snow avalanches may subside, but expect it still to be a problem in steep terrain for skiers/climbers. Touchy cornices developed through the storm are new trigger to consider when assessing overhead terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 23rd, 2016 4:00PM